This invention relates to a heating oven, especially but not exclusively for use in ageing semiconductors.
Semiconductor devices such as silicon chip integrated circuits are prone to failure early in their lives, and it has previously been proposed to accelerate the natural ageing of the semiconductors by subjecting them to controlled heating before they are put in use. Such heating, or "burn-in" has the effect of exponentially accelerating the semiconductors through their life, so that their first year of life can be represented in, typically, 48 to 64 hours.
On testing the semiconductors after the ageing process, those which have failed can be picked out, leaving only the operational units. First-year failures in use can thus be greatly reduced.
Semiconductors have previously been aged in heating ovens into which trays of the semiconductors are place. As close temperature tolerances have to be observed, the heating cycle has to be completed before the oven door is opened and the units inspected. Thus all the units are heated simultaneously, and it can be difficult to isolate faulty units from operational ones during the process. Also, the process is a pure "batch" process which does not allow for sequential treatment of the units.